You need a 4.7K pullup resister from +5v to the 1-wire signal when running in parasite mode. See the maxim-ic spec sheet figure 1 page 3 which shows the 4.7 K pullup resister. I am running in parasite mode. I started with a bowl of ice water which contained the DS18B20 sensor and an inexpensive digital thermometer that I would not count on being linear. Removed the ice cubes and logged the two temperatures as the bowl of water warmed to room temperature.

The following are the Fahrenheit values from the digital thermometer and the Centigrade values from the EZIO8SA.